wc will try to bring up questions about the possible "injury" being from the off work activities too.
even if you have eye witness to the injury happening at work - the info about your hobbies & personal activities will bring up questions...

sorry but it's the way they play the game

IMO- You'll need a very strong and experienced atty to fight with the preexisting stuff and the hobbies/activities involved.

explore our wc forum for tips and more info on that side of it.

best of luck to you..